I find it crazy that you’re bothered by scans having a margin of error measured in single digit days.
It is a problem because if you run out of the pre determined terminus based on erroneous scans you will get c-section because protocol.
Of course this is a personal anecdote and may not apply to your country.
Might be worth reviewing the ACOG's recommendations on post-term deliveries https://www.acog.org/clinical/clinical-guidance/committee-op...
I'm saying that you need to tell that to the doctors, who raised all manner of forcible induction on the mother at N+1 days.
Why is a week within margin, but the day after due date isn't?
You say "the baby will come out when they're ready", but what would you reply to "what if the baby wants to come out stillborn?"
When do you want forcible induction to be advised by the clinician? 39 weeks + 2-3 days for you to feel comfortable about the decision? Maybe a week if you're seeing a psychologist or like astrology?